1. Field of the Invention
The present invention relates in general to novel pharmaceutical intermediates and, more particularly, to novel indole derived pharmaceutical intermediates and methods for preparing the same. The novel compounds of the present invention are preferably suitable for participation in direct or multi-step convergent syntheses with other compounds including, but not limited to, aldehyde derived pharmaceutical intermediates, etcetera.
2. Background Art
The commercial development of novel pharmaceutical compounds is, often times, replete with arduous problems relative to transitioning from research and development scale to plant scale synthesis. A plurality of complex issues, including reagent cost, reaction yield, reaction time, competitive side reactions, product isolation and/or purification, disposal of toxic waste and/or byproducts remain largely problematic for the scale-up of most pharmaceutical endeavors.
Problems associated with preparing novel pharmaceutical compounds can become exponentially difficult when, for example, intermediates comprise delicate compounds where one or more atoms, functional groups, and/or moieties need to be associated with a protecting group during one or more steps of a synthesis. For example, hexahydroazepinoindole-carboxylate intermediates comprise a nitrogen atom on the heptacyclic moiety which is commonly protected with a benzyl group during multi-step synthesis. However, obtaining a final product normally necessitates removing the benzyl group which is a great liability—especially at commercial scale. Notably, copious quantities of expensive catalyst (e.g., palladium) must be used to remove the benzyl group. To make matters more complex, reaction conditions are such that significant side reactions occur, thereby: (1) adversely affecting the net yield; (2) materially increasing product cost; and (3) substantially increasing isolation and purification difficulties. Notably, the above-identified problems are very difficult to solve because other types of classical protection of the nitrogen atom—such as carboxybenzyl groups or amides can prevent a desired reaction sequence altogether.
While indole derived pharmaceutical intermediates have been the subject of recent study, to the best of Applicant's knowledge, no such intermediates have been identified today that facilitate practical transition from research and development scale to commercial, plant scale synthesis.
It is therefore an object of the present invention to provide novel indole derived pharmaceutical intermediates and their syntheses which will partially and/or fully remedy the above-identified issues associated with the commercialized development of pharmaceuticals.
These and other objects of the present invention will become apparent in light of the present specification, claims, chemical structures, chemical formulae, and drawings.